Mayor Bill de Blasio and his senior staff repeatedly tried to pressure the commissioner of New York City’s top watchdog agency into not releasing critical reports about his administration, the commissioner said Monday.

Days after being fired from his job as the head of the Department of Investigation, Mark Peters said in a letter to the City Council that the mayor and at least two deputy mayors upbraided him on several occasions during his time in the post, accusing him of disloyalty and questioning whether he was “still a friend” to Mr. de Blasio.

Each rebuke, Mr. Peters said, came right before his agency released reports critical of the administration, including a November 2017 report on the city failing to conduct proper lead inspections at its public-housing developments and an April 2017 report about the misuse of city-owned cars by top brass at the Department of Correction.

“On several occasions the mayor and his most senior staff have expressed visible anger at me over certain DOI investigations,” Mr. Peters said in the letter. “They have requested that I not issue certain reports, and when I declined to do so they took actions to demonstrate their anger in ways that were clearly designed to be intimidating.”

Mr. Peters said the intimidation turned to punishment on Friday, when Mr. de Blasio fired him as commissioner and replaced him with Margaret Garnett, New York’s executive deputy attorney general for criminal justice and a former federal prosecutor. His dismissal from the position he had held since 2014 was a way to silence him and thwart coming investigations that pertain to the mayor and his senior staff, according to the letter.

.. Under city rules, he was allowed to provide a public response to his firing.

.. In firing Mr. Peters, the mayor cited an independent probe’s determination that Mr. Peters abused his power earlier this year when he tried to absorb an investigative agency for the city’s Education Department into the DOI. Two people whom Mr. Peters fired during that reconfiguration filed whistleblower claims.

Following the release of the independent probe’s findings last month, Mr. Peters issued a public apology and admitted his actions were wrong.

No matter how much the president loves them, the government can only enforce nondisclosure agreements for classified information.

Part of the outrage on the president’s part seems to be over Manigault Newman breaking what Trump saw as a promise not to talk about her time working for him. White House counselor Kellyanne Conway told ABC News: “We have confidentiality agreements in the West Wing — absolutely we do.” And Manigault Newman claims in her book that Trump’s reelection campaign offered her a $15,000-a-month salary in exchange for signing a confidentiality agreement.

.. NDAs for government workers, when they go beyond prohibiting the disclosure of classified information, are unconstitutional on their face.

.. For decades, courts have made it clear that the government may not censor unclassified material, “contractually or otherwise.”

.. I have reviewed one document that is purportedly a version of the White House NDA. It appeared to be nothing more than a Trump Organization document that was modified to apply to White House staff — in fact, it still had a provision that in any litigated dispute, the parties agreed that New York state law would apply, language that no standard federal document would ever have used.

.. It was also publicly reported that one early draft of a White House NDA contained a provision that imposed a $10 million fine to be paid to the federal government if the signatory shared confidential information.

.. While the term “confidential” in D.C. parlance is part of the national security classification framework, in these NDAs, it referred to potentially derogatory and unclassified information pertaining to the president.

.. These NDAs also ignored earlier guidance from the Office of Management and Budget that any NDAs should contain whistleblower protection provisions, clauses that would be contrary to the clear message desired by this administration.

.. his campaign entity, Donald J. Trump for President Inc., rather than the U.S. government, has reportedly filed for arbitration against Manigault Newman seeking millions for a violation of a 2016 NDA.

.. The NDA allegedly required her to keep proprietary information about the president, his companies or his family confidential and to never “disparage” the Trump family “during the term of your service and at all times thereafter.” This clause is in direct conflict with the legal precedents governing federal employees, but how an arbitration body will interpret constitutional questions is anyone’s guess.

“I think they should,” Trump said. “. . . When people are chosen by a man to go into government at high levels, and then they leave government and they write a book about a man and say a lot of things that were really guarded and personal, I don’t like that.”

.. In 1961, President John F. Kennedy said the “very word ‘secrecy’ is repugnant in a free and open society; and we are as a people inherently and historically opposed to secret societies, to secret oaths and to secret proceedings.”

To all those supposed constitutional conservatives out there, consider this your call to arms: The First Amendment is under direct attack, and this time from a much more powerful foe than misguided college freshmen.

By whom I mean: the ostensible leader of the free world.

Again and again, President Trump has used the weight of his office and the broader federal government to inflict financial damage upon critics, whistleblowers, journalists and peaceful protesters for exercising their rights to free speech.

Trump’s most recent salvo involves former CIA director John Brennan. During his long career in intelligence, Brennan briefed Republican and Democratic presidents alike. Which makes his fierce criticism of Trump, and his characterization of Trump’s Helsinki performance as “treasonous,” all the more biting.

.. Such comments led Trump to revoke Brennan’s security clearance Wednesday. The administration said Brennan no longer needed clearance because it didn’t plan to call on him for consultations. But high-level clearances are valuable for private-sector work as well.

In other words, this was about shutting Brennan’s mouth by going after his wallet.

.. And that is but one way Trump has tried to silence critics just this week.

A day earlier, Trump’s campaign said it had filed an arbitration action against Omarosa Manigault Newman alleging that the former White House aide broke a 2016 nondisclosure agreement by publishing her recent tell-all book.

.. And that is but one way Trump has tried to silence critics just this week.

That the party bringing the claim here is technically a campaign, rather than, say, the Justice Department, doesn’t matter. The First Amendment is supposed to protect those critical of their government, including critics of its highest officeholder, from political retribution. And political retribution laundered through an election campaign at the president’s instruction is retribution all the same.

.. Elsewhere — again, in recent days — the president and his minions have called the press the enemy of the people and the opposition party. Previously they have blacklisted reporters and entire news outlets (including The Post) whose questions Trump disliked.

.. When unhappy with Post coverage in particular, Trump has threatened government action against Amazon in an apparent attempt to financially punish its chief executive, Jeffrey P. Bezos, who independently owns the paper.

.. Journalists and media owners are hardly the only ones whose job or financial security Trump has targeted from his bully pulpit. He called for the firing of National Football League players who kneel in protest during the national anthem. NFL owners, in a secretly recorded meeting in October, expressed concern about the president’s impact on their bottom line.

Curiously, Republican politicians and conservative pundits who call themselves staunch defenders of the Constitution have allowed, and at times encouraged, the president to run roughshod over the First Amendment.

Sen. Charles E. Grassley (R-Iowa), who as chair of the Senate Judiciary Committee oversaw a hearing titled “Free Speech 101: The Assault on the First Amendment on College Campuses,” refused to condemn Trump’s calls for the firing of NFL players engaged in peaceful protest. Instead, in September, he attacked the media for giving the “false impression” that Trump spent too much time attacking the NFL.

.. Polls in the past couple of years have shown that pluralities and, quite often, majorities of Republicans say that they, too, consider the media the enemy of the people; believe that the president should have the authority to close news outlets that he believes behave badly; and favor firing NFL players who refuse to stand for the anthem and stripping citizenship from anyone who burns the flag.

WASHINGTON — For years, President Trump has used Twitter as his go-to public relations weapon, mounting a barrage of attacks on celebrities and then political rivals even after advisers warned he could be creating legal problems for himself.

Those concerns now turn out to be well founded. The special counsel, Robert S. Mueller III, is scrutinizing tweets and negative statements from the president about Attorney General Jeff Sessions and the former F.B.I. director James B. Comey, according to three people briefed on the matter.

.. Several of the remarks came as Mr. Trump was also privately pressuring the men — both key witnesses in the inquiry — about the investigation, and Mr. Mueller is examining whether the actions add up to attempts to obstruct the investigation by both intimidating witnesses and pressuring senior law enforcement officials to tamp down the inquiry.

.. Trump’s lawyers said. They argued that most of the presidential acts under scrutiny, including the firing of Mr. Comey, fall under Mr. Trump’s authority as the head of the executive branch and insisted that he should not even have to answer Mr. Mueller’s questions about obstruction.

But privately, some of the lawyers have expressed concern that Mr. Mueller will stitch together several episodes, encounters and pieces of evidence, like the tweets, to build a case that the president embarked on a broad effort to interfere with the investigation. Prosecutors who lack one slam-dunk piece of evidence in obstruction cases often search for a larger pattern of behavior, legal experts said.

.. the nature of the questions they want to ask the president, and the fact that they are scrutinizing his actions under a section of the United States Code titled “Tampering With a Witness, Victim, or an Informant,” raised concerns for his lawyers about Mr. Trump’s exposure in the investigation.

.. “If you’re going to obstruct justice, you do it quietly and secretly, not in public,” Mr. Giuliani said.

.. federal investigators are seeking to determine whether Mr. Trump was trying to use his power to punish anyone who did not go along with his attempts to curtail the investigation.

.. Investigators want to ask Mr. Trump about the tweets he wrote about Mr. Sessions and Mr. Comey and why he has continued to publicly criticize Mr. Comey and the former deputy F.B.I. director Andrew G. McCabe, another witness against the president.

.. They also want to know about a January episode in the Oval Office in which Mr. Trump asked the White House counsel, Donald F. McGahn II, about reports that Mr. McGahn told investigators about the president’s efforts to fire Mr. Mueller himself last year.

.. Mr. Trump has navigated the investigation with a mix of public and private cajoling of witnesses.

.. Around the time he said publicly last summer that he would have chosen another attorney general had he known Mr. Sessions was going to recuse himself from the Russia investigation, Mr. Trump tried behind closed doors to persuade Mr. Sessions to reverse that decision. The special counsel’s investigators have also learned that Mr. Trump wanted Mr. Sessions to resign at varying points in May and July 2017 so he could replace him with a loyalist to oversee the Russia investigation.

.. Mr. Trump issued an indirect threat the next day about Mr. Comey’s job. “It’s not too late” to ask him to step down as F.B.I. director, he said in an interview with Maria Bartiromo on Fox Business Network. The special counsel wants to ask the president what he meant by that remark.

.. Mr. Sessions, his aide told a Capitol Hill staff member, wanted one negative article a day in the news media about Mr. Comey, a person familiar with the meeting has said.

.. By the fall, Mr. Comey had become a chief witness against the president in the special counsel investigation, and Mr. Trump’s ire toward him was well established. His personal attacks evolved into attacks on Mr. Comey’s work, publicly calling on the Justice Department to examine his handling of the Clinton inquiry — and drawing the special counsel’s interest.

.. Mr. Trump’s lawyers have pushed back against the special counsel about the tweets, saying the president is a politician under 24-hour attack and is within his rights to defend himself using social media or any other means.

.. The president continues to wield his Twitter account to pummel witnesses and the investigation itself, ignoring any legal concerns or accusations of witness intimidation.